Submission #203668

#	Time	Username	Problem	Language	Result	Execution time	Memory
203668		cheetose	Sparklers (JOI17_sparklers)	C++11	50 / 100	181 ms	16040 KiB

sparklers

#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define X first
#define Y second
#define y0 y12
#define y1 y22
#define INF 987654321987654321
#define PI 3.141592653589793238462643383279502884
#define fup(i,a,b,c) for(int (i)=(a);(i)<=(b);(i)+=(c))
#define fdn(i,a,b,c) for(int (i)=(a);(i)>=(b);(i)-=(c))
#define MEM0(a) memset((a),0,sizeof(a));
#define MEM_1(a) memset((a),-1,sizeof(a));
#define ALL(a) a.begin(),a.end()
#define SYNC ios_base::sync_with_stdio(false);cin.tie(0)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> Pi;
typedef pair<ll, ll> Pll;
typedef pair<ld, ld> Pd;
typedef vector<int> Vi;
typedef vector<ll> Vll;
typedef vector<double> Vd;
typedef vector<Pi> VPi;
typedef vector<Pll> VPll;
typedef vector<Pd> VPd;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef tuple<ll, ll, ll> LLL;
typedef vector<iii> Viii;
typedef vector<LLL> VLLL;
typedef complex<double> base;
const int MOD = 998244353;
ll POW(ll a, ll b, ll MMM = MOD) { ll ret = 1; for (; b; b >>= 1, a = (a*a) % MMM)if (b & 1)ret = (ret*a) % MMM; return ret; }
ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
ll lcm(ll a, ll b) { if (a == 0 || b == 0)return a + b; return a*(b / gcd(a, b)); }
int dx[] = { 0,1,0,-1,1,1,-1,-1 }, dy[] = { 1,0,-1,0,1,-1,1,-1 };

int n,k;
ll t,a[1000];
Pll d[1000][1000];
bool ok(ll m)
{
	fup(i,0,n-1,1)fup(j,0,n-1,1)d[i][j]=mp(INF,-INF);
	d[k][k]=mp(a[k],a[k]);
	fup(kk,1,n-1,1)
	{
		fup(i,0,n-1-kk,1)
		{
			int j=i+kk;
			if(d[i+1][j].X<=d[i+1][j].Y && d[i+1][j].X-t*m<=a[i]+t*m*kk)
			{
				d[i][j].X=min(d[i][j].X,max(d[i+1][j].X-t*m,a[i]-t*m*kk));
				d[i][j].Y=max(d[i][j].Y,min(d[i+1][j].Y+t*m,a[i]+t*m*kk));
			}
			if(d[i][j-1].X<=d[i][j-1].Y && d[i][j-1].Y+t*m>=a[j]-t*m*kk)
			{
				d[i][j].X=min(d[i][j].X,max(d[i][j-1].X-t*m,a[j]-t*m*kk));
				d[i][j].Y=max(d[i][j].Y,min(d[i][j-1].Y+t*m,a[j]+t*m*kk));
			}
		}
	}
	return d[0][n-1].X<=d[0][n-1].Y;
}
int main() {
	scanf("%d%d%lld",&n,&k,&t);k--;
	fup(i,0,n-1,1)scanf("%lld",a+i);
	ll l=0,r=1000000000;
	while(l<=r)
	{
		ll m=l+r>>1;
		if(ok(m))r=m-1;
		else l=m+1;
	}
	printf("%lld",l);
}

Compilation message (stderr)

sparklers.cpp: In function 'int main()':
sparklers.cpp:75:9: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   ll m=l+r>>1;
        ~^~
sparklers.cpp:70:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%lld",&n,&k,&t);k--;
  ~~~~~^~~~~~~~~~~~~~~~~~~~~
sparklers.cpp:71:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  fup(i,0,n-1,1)scanf("%lld",a+i);
                ~~~~~^~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 20 / 20
• Subtask 3: 0 / 50